Crack Stitching using HeliBars
Stabilising cracked masonry using HeliBars and HeliBond grout
HeliBars bonded into appropriate bed joints or cut slots is the solution to stabilising cracked masonry. HeliBars bonded horizontally into the masonry work to redistributed structural loads along the masonry and to minimise further developments of the crack.
BENEFITS
- Quick, simple, effective and permanent.
- HeliBar and HeliBond grout combine to produce an excellent bond within the substrate.
- Masonry remains flexible enough to accommodate natural building movement.
- Non-disruptive structural stabilisation with no additional stresses.
TECHNICAL SPECIFICATIONS
- Available diameters - 6mm (8 and 10mm also available).
- Available lengths - 1m (standard) to 7m.
- Material - Austenitic grade 316 stainless steel.
- Vertical spacing - Every 4 brick courses (340mm).
- HeliBars per slot - 1 HeliBar for each skin of brickwork (e.g. 1 HeliBar per slot to crack stitch a single leaf or 2 HeliBar per slot to stitch a 230mm solid wall).
- Depth of slot - Single skin/cavity wall 25-35mm Solid wall 35-45mm.
Repairing cracks near corners and openings
Where cracks are less than 500mm from an external corner (A) or an opening (B) at least 100mm should be bent around the corner and bonded into the return wall or bent and fixed into the reveal, avoiding any DPC membrane.
Points to Note
- Where two or more cracks are close together these may be stitched using one continuous length of HeliBar which must be long enough to extend 500mm beyond the outer cracks. For example, if there are three cracks, each 250mm apart, then the overall length of HeliBar required would be 1.5m.
- The horizontal slot, normally the mortar bed, can be cut using a twin diamond blade chaser with vacuum attachment, an angle grinder or a mortar chisel.
- All mortar must be removed, together with any loose debris, to ensure a sound bond.
- Prepare the slot with HeliPrimer WB or thoroughly wet the slot with clean water.
- As standard, slots should be 10mm wide to accommodate the 6mm diameter HeliBar.
- HeliBond grout is the recommended bonding agent. Resin is used for smaller jobs and where loads are to be rapidly applied.
- Compatible with lime mortars.
INSTALLATION
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Rake out or cut slots into the horizontal mortar beds, a minimum of 500mm either side of the crack, to the specified depth.
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Clean out slots with blow pump and apply HeliPrimer or flush with water.
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Using a Helifix Pointing Gun, inject a bead of HeliBond to the back of the slot.
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Using a finger trowel, or similar, push the HeliBar into the grout to obtain good coverage.
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Insert a further bead of HeliBond over the exposed HeliBar, finishing 10-15mm from the face, and ‘iron’ into the slot using a finger trowel.
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Repoint the mortar bed and make good.
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Make good the vertical crack with an epoxy-based weatherproof filler, e.g. CrackBond. More...
